Telephone system.



H. J. MEREDITH. TELEPHONE SYSTEM. APPLiCATlON HLED rm. 6, 1915.

1.1 88.002. Patented June 20, 1916.

2 SHEETSSHEET 1.

1 6T avnnutoz H. J. MEREDITH.

TELEPHONE SYSTEM.

APPLICATION FILED FEB 6, 1915.

lutvnted June 20, 1916.

22 i Lia/bi 2,48

Puma BUTTON Wfluamo E HENRYJ.MERED TH Wm.8 q- T Q aka M 41 wwwgew Chicane I or.

HENRY J. MEREDITH, OF HOLYOKE, MASSACHUSETTS.-

TELEPHONE SYSTEM.

1 ,iss,oo 2.

Specification of Letters Patent.

. Patented June 20, 1916.

Application filed February 6,1915. Serial No. 6,533.

To all zchom it in try can er-n Be it known that I, I'll-iNltY J. ltli-iniaorrii,

a citizen of the liniled States, residing at llolyoke, in the county of I1lainpden and 5 State of i\lassachusetts, have invented certain neiv'and' useful Improvements in Tele phone Systems, of which the following is a specification, reference heiiig had to the accoiiipanying drawings. I

My invention relates to telephone systems, and particularly to a telephone system wherein an alternating insteadof a direct current is used.

The prin'iary object of my invention is to so arrange the system tliat an alternating current may be used for the purpose of trans i'nitting sound telephonically, and thus the distance over which sound may .he trans mitted may be greatly increased, without, however, diminishing the sound received by I the-receiver, but on the other hand, increasing the distinctness of the transmitted sound. A further oliject'of the invention is to provide for steppingdown the voltage of 25' the current received from the source of" power to-the'proper voltage for the transmitter-andstepping up this voltage to that proper to lie usedEin the receiver, and also step up the voltage when it is desired to iiicrease the length of the line so as to transmit sound to greater distances.

A ful'tlieroliject is to provide for continuous SClf-il'ldliCt'lOil throughout the entire telephone system uid in the transformer connections on the principle of a choke coil so that the current in the pr-iniary circuit shall vary directly as the load on the secondary.

Still. another object is to provide means for dampening or quietiug the transmission by the use of condensers connected. in multiple with thepriinary or secondary coils of thetransformer used for stepping down the voltage of the alternating current.

46 Other objects will appear in the course of the following description.

My inventionis illustrated in the acconipanying drawings', wherein- Figure 1 is a diagram of a telephone systern arranged .in accordance,with my iii vention; Fig. 2 is a like view to Fig- I, showing the use of condensers; Fig. 3 is a diagram showing a different arrangement of the telephone circuit; Fig. 4 is adiagram showing a telephone system wherein power is secured from a plurality of currents; Fig.

ment of the system, and Fig.

'- the ,voltage of currents 5 is a diagrammatic view showing my sys' tem applied whermone transmitter is used with .a. plurality of receivers; Fig. G'is a diagran niat-ie view showii'i another arrange- 7 is a diagram showing adifferent means for controlling passing vover the circuit.

Referring now to Fig. 1 designates the wires or coinluctors leading from a source of low frei'nieucy, single phase alterrating current totlie primary coil 3 of a transformer whose secondary winding. or coil is designated 4. An idjustahle 'coreS is used in the transformer which is adjustable so as to control the current induced in the secv ondary win-ding of said transformer. This core is preferably laminated.

of any suitable clniracteit, and that I have onlyillustrated it diagraniniatically. Lead- 7 I It..is to be understood that this transformer may; be

ing from the secondary coil of the trans- I former are the conductors- 3-(3 forming a seiz iiiilzii-y circuit in which is included the |)lllll;ll winding i of; a transformer 8, and

also inciuded in said circuit is the transmittcr The secondary coil 1001': the transformer 8 is connected iircircuit with. a recciver ll of any suitable 'Clftll'iltJZOl. The line wires 12 are conncctcal in multiple with the secondary circuit (Ti-16 and a tra nsn'i'itter l3,

and the priinar winding l i. of a.traiisformer 15 is also connected in multiple with the line wires 7-T. Coacting with the primary winding li'of the tiransforn'ier is the secondary winding-1G connected in (air-- cuit with the receiver 17. j

it will lie umlcrstood that the voltage of the alternating current in the wires (3 (i is lower than the. voltage in the wires 9-2,.

through this current lacing stepped down laythe transformer and 5, and that thiscurrent is stepped .up by thetraustormer 8 so that it may Infused-Ito actuate the receiver where a relatively high degreeof voltage is required.

In Fig. 2 I. show a circuit arrangement pract.icall 'similar to that shown in Fig. 1, hut in which the primary wires of the traiisfornier 1 connected with the source of energy are connected in multiple with the condenser 18. I may connect one or more condensers in multiple in circuit with the source of energy transformer, as previously described, across the primary leads of the transformer. Als in Fig. 2 I show a con denser 19 connected across the line wires (36. I may use one or more condensers connected in multiple, however. It is not essential that these condensers in Fig. '2 he used under all circumstances, their use'depending on the requirements of the system. In Fig. I show a circuit 20 including a secondary 21 of a' transforxne1 22, the primary coil of which is connected to a source ofalternating current, this circuit also ineluding in it aplurality of primar transformer coils 23 and a transmitter '34. Coacting with each of the primary coils 23 of the step up transformers is a receiver circuit having therein thesecondary coil 25 of the transformer. It willhe seen that the prin ciple of this arrangement is precisely the same as the principle illustrated in Fig. 1.

In Fig. 4 I show a telephone circuitso arranged that it receives'energy at a plurality of points in the system. Thus in this figure, 26, 26 and 26 designate the primary windings of a plurality ofstep down transformers, each of these primary windings being connected with a source of alternating current. The secondary windings 27* and 27" of the transformers 26 and 26* are each connected in circuit witha transmitter '28 and with the primary coil 29 of a transformer whose secondary coil 30 is in circuit with the receivers 31. The primary coil 26 coacts with the secondary coil 27 in circuit with a transmitter 28 and a primary coil 32 of a transformer whose secondary 33 is connected in circuit with the coil 30 and the receivers 31. A condenser 34 is also interposed in the circuit, as illustrated in Fig. 4 and for the purpose heretoforedescribed. In Fig. 5 I show a system wherein the receivers 35 (as shown in full lines) are connected in series with the secondary winding 36 of a transformer whose primary windin}, 37 is connected in circuit with the transmitter and with the secondary of a step down transformer 3d having an adjustab core. as described in Figs. 1 and In dotted lines in Fig. 5 I show that the ceivers 35 might he connected in multiple as well as in series, as I do notwish to be limited to the use of the receivers in series.

In Fig. (3 another arrangement is illustrated wherein signals are arranged in corn nect-ion with each telephone. In this figure 40 dcsigi'iates the primary winding of a transformerconnected with a source of al tcrnatiu; current, and 41 designates the sec cndary winding thereof. This secondary winding is connected in circuit with the pri mary winding: 42 of a transformer whose secondary winding, is connected in circuit with the receiver 43. Also disposed in this circuit is a transmitter 44; andth circuit is.

This

normally broken by a hook switch 45. hook switch normally connects the secondary it ill 'CIICIHC with a signal hell 46, in

turn connected to a. ground, the other side of the coil 41 being connected to a ground 47, there being a signal lamp disposed also in this circuit. Instead of grounding the circuit. however, a return conductor 48 might be used. which is illustrated in dotted lines. I have also illustrated in this figure a second circuit connected with the first and operating: in the same manner. I I

In Fig. 7 I show an arrangement whereby the volume 'of the transmitted energy may he increased without shifting the coil of the transformer. In this connection the secondary coil 50 of the transformer, whose primary coil is designated 51, has a plurality of taps or connections 52, each leading from a different point of the coil. The conductor of the line is connected with an adjustable arm 54 or switch which may be shifted into elcctricalengagementwith any one of the taps, thereby using a part of the coil as reactancc. according to the exigencies 'of the situation.

It will be noted that a continuation of the transtorming of the current eithei by stepping the current up or stepping it down will carry the sound waves to a greater distance. Thus in Fig. 7 I have shown the line wires as running to a primary 56 of a transformer. the secondary 57 of which connected with the primary winding 58 of a transformer whose secondary 59 is connected to line wires 60.

While I have illustrated many diagrams showing different arrangements of my sys tem, it will be seen that in all these diagrams t- 1e same principle of operation is used, and that in all the. systems illustrated continuous self-induction is produced. and throughout all the systems the step down and step up transformers are used for the purpose of increasing or decreasing the voltage of thi-v current. use lot the extra step up transformers I am able to transmit a further distance than could otherwise-he-attaiiied. and that in this case the primary of the extra step up transtormer'is in circuit with the secondary of the first step up transformer, while the secondary of the extra step up transformer is connected to the line. It will be seen that with my telephone system it is not required that the energy be derived from a primary or secondary battery in the transmitter cireuit. Instead it is the alternatingcurrent. which varied throughoutthe entire length of the circuit by the action of the transmittor. q

It is to be noted that self induction is alwa present where a cliche coilis counectcd in circuit with an alternating current. It a choke coil is placed in circuit with an alternating current, as illustrated in the diagrams previously descrihed, it produces a lagging cliect on the current. Thus these It will also be seen that by the.

transformers tend to IGfiCt on 91103: 'other and qui et theheavy buzzing whisk; 'wmld be othel'wise presvm. The two srlmlw mils are in serie, one the fwt jiflldll l of the hwuw farmer mmnecteii with She smmiw vi energy and the other: as the primary of QM swnml I'll-s this lam: I35

i flow missian of the voice to many plncos at the 9mm,- fiime. Thus the system illustrated in Fig. 5 or that illu h'ated in Fig, 3 may be 115ml fur :mnmm-zthlg pnrpuws; in lnz'ge halls and gmhlzc places, as in railmml mummy tlllll in irn l My teleplmne system nmy bu used in ma :nzu'y telephone plxu'tico of any (l0 illmh'zmwl in the ii'l'uils.

tramsfmum; tlw scr-oudary ul' whivh ineludes av receiver, the several transformers when directly connected through connecting lines operating to prevent leakage, and acapacity in shunt with the transmitter.

5 In a telephone system, the combination with a source (if-alternating current, associated with the primary winding of a variable magnetic circuit static transforn'ler, of a plurality of circuits, a secondary Winding 0 inductively connected to said transformer and :1 circuitin series with the primary winding of another Stzitic transformer, a. condenser in multiple with said circult, and a transmitter in said circuit.

In testimony whereof I hereunto afiix my 15 signature in the presence of two witnesses. HENRY J. MEREDITH.

Witnesses P. J. GARVEY, E. A. KILLRnm. 

